Pitless adapter

I have a 150 ft well with a submersible pump. My pitless adapter is allowing surface water to trickle in. I am going to replace it as it is several decades old. I was wondering if there is an obvious "best" adapter available or if several companies make (sell) them. Thanks for your help.

I'd be suprised if you pitless actually leaks surface water, maybe a leak in the o'ring so maybe leaking well water back down the well. If it leaks it basically means that whoever put it in did a really shotty job. You'll probably have to weld on a patch where it currently is. As far as pitless adpaters go, i really dont have a preference, usually get the cheapest.